Articles
Road & Track's Report on the 1989 SC


THUNDERBIRD SUPER COUPE
A more powerful, more sophisticated Bird emerges from Ford's nest

STEALING BASES, ROLLING dice and building cars that don't fit current market trends are actions that fit within the general category of risky business. Risky business is not big business. The contradiction here, of course, is that Ford Motor Co has built a new Thunderbird that does not comfortably fit current market thinking-and Ford is definitely big business.

To find out more about the newly hatched 'Thunderbird, we went to Ford's Dearborn, Michigan proving ground and put a $450,000 pre production prototype of the Thunderbird Super Coupe through our regular track test. Keeping in mind that this test vehicle was a prototype is important. Ford's spokesman pointed out that this was the same tired Thunderbird SC that scores of development engineers and auto journalists had flogged without mercy all summer. While production versions of the car should yield similar performance, final engine, suspension and braking calibration may be slightly different.

The Super Coupe engine is a 90-degree V-6 force-fed with an Eaton Corp supercharger. The V-6 displaces 3.8 liters and has a modest compression ratio of 8.2: 1. Fuel is supplied by six sequentially squirting fuel injectors. At its maximum spooling rate (15,600 rpm), the supercharger forces approximately 12 psi of boost into the intake tract, with a resultant 210 bhp at 4000 rpm. But the real news is the 315 lb-ft of torque that's available at just 2600 rpm. Those who recall the effortless slow-rev grunt of big V-8s will feel right at home behind the SC's thick-rim steering wheel. Last year, the T-Bird's top engine offering, the 2.3 liter turbo-intercooled four, made a respectable 190 bhp at 4600 rpm and 240 lb-ft of torque at 3400 rpm. The big difference is that while the old 2.3 vibrated noticeably, the 3.8 puts power to the rear wheels with the smoothness of a monster electric motor. Inside the cabin, blower noise is quite low in most operating ranges. Our tester, however, did detect a bit of mid-range growl from the stainless steel exhaust system. But the tone and volume seemed appropriate to the power being developed.

Asked about rumors that Ford was having troubles with blown head gaskets, we were told that the difficulties were just teething problems. One Ford engineer put it this way: "All of the gremlins appeared very early in the development process on engines that were being pushed hard without all of the fuel-injection and ignition electronics work finished. Today, that engine is bulletproof."

T-Bird's bold new shape looks great from any angle. The supercharged V-6 delivers ample power without much noise. The interior, while functional, breaks no new ground.

The 5-speed manual transmission Ford is using is an all-new Mazda design. Beefed up significantly to handle the supercharged engine's low-end torque, there's a chance that it may later go into some of Ford's trucks. Speaking of trucks, we remarked to the attending engineer that the shift effort seemed a tad high. He informed us that the effort had been even higher when the first versions arrived from Mazda and that we had the loudly protesting voice of none other than Jackie Stewart to thank for the improvement. Further, we were told the work continues that should further reduce the linkage's effort before production.

In any case, the shifter in the prototype simply didn't have the polished feel that a manual transmission in this type of car requires. In fact, the shift action in the Borg-Warner T5 in last year's car felt slicker, despite its longer throws. But after several botched familiarization runs, where a strong clutch-return spring and slightly notchy transmission shift gate made their presence known, an adequate number of clean sub-7.5-second runs to 60 were recorded. By comparison, recent 0 60-mph acceleration tests revealed the following times for cars with similar sporting intentions: Acura Coupe, 7.7 see; BMW 325is, 7.5 see; and Pontiac Grand Prix SE, 9.7 sec. And obviously, the T-Bird breathes well all the way up through the gears with a quick quarter-mile time of 15.9 see at 88.5 mph. Ford says the cars terminal velocity is 140 mph, but time and the Dearborn track's small size precluded any top-speed testing.

If you have trouble shifting for yourself, don't despair. A 4-speed automatic featuring 0.67:1 overdrive ratio and an electro mechanical lockup to eliminate torque-converter slippage is available with the supercharged engine.

So with all of this thrust, what kind of braking system does the Thunderbird feature? There is a vented disc brake at each comer, with front diameter being 10.8-in. The rear axles are shod with 10.0-in. rotors. And all four are controlled by an electronic anti-lock braking computer that's standard on the SC. (This system is optional on the base and LX versions of the Thunderbird.)

The numbers generated in the braking lane were quite good-but not as good as those for last year's car. The SC stopped in 140 ft from 60 mph; the Thunderbird Turbo Coupe stopped 9 ft shorter. From 80 mph, it took the SC 247 ft; the turbo car used 243 ft of the lane. It's important; however, to note that last year's Thunderbird was one of the best-stopping production sedans we reviewed. BMW's 635CSi, one of the new T-Bird's target vehicles, used 263 ft during its 80-0-mph brake-lane trial. Considering the additional curb weight of the new car, the stops are quite acceptable.

The visual impression Ford hopes to get across with the car's new styling is one of menacing elegance-sort of like Chuck Norris in evening dress. And to create that impression of compact muscularity, the new car rides lower, the wheelbase was lengthened 9 in., the front and rear tracks have been widened, and the body surfaces are now clean and uncluttered. Although the new T-Bird looks longer, it's actually 3.4 in. shorter than the previous car. Also adding to this low, ultra-slick appearance is flush window glass, a longish hood, a short cowl height, a low beltline, narrow aero headlamps and a laid-back (63.9-degree) windshield angle. Ford stylists felt this styling tack would also accentuate the car's rear-drive visual signature.

Functionally, it's hard to fault the new interior-except for the motorized shoulder-harness system. As Ford proudly points out all of the front-seat measurements are greater than in last year's model. The rear-seat area definitely feels roomier than the rear nest in the old T-Bird. That's because Ford has widened the rear hip space by 7 in. and increased leg room, owing to the longer wheelbase. The sharply contoured front buckets are adequately supportive when the car is being tossed hard. But our brief seat-of-the-pants impression is that the company could have stuffed the cushions with a higher-density foam. The standard gauges are large, round analog-types that are easy to read. The controls are logically and conveniently located. The radio is located high in the dash-an eye-flick to the driver's right. The cruise-control buttons are on the steering-wheel hub. The headlight switch is a familiar push-pull type mounted high and to the left. But while the car's exterior has a daring look that suggests the styling envelope was stretched, the SC interior appears to be a halfhearted freshening of a Tempo's instrument panel and interior trim.

Ford claims that lots of attention has been lavished on making sure that the controls in the production vehicles will have the appropriately expensive appearance and feel. This was done by comparing the 'r-Bird pieces directly against those in cars such as the Mercedes-Benz 190E, Toyota Supra and BMW 6-Series. But it wouldn't be fair to discuss fit or finish based on our test vehicle, and it's a sure bet that production versions of the car will be better.

Attached to the underside of the floor pan of the re-styled body are small front and rear subframes. These units are steel frames to which the suspension, powertrain and steering gear components are attached. One of the important advantages with them is very nearly the same noise- and vibration-attenuation ability as a separate full frame. Another advantage is easier collision repair. In front, remove eight bolts and the entire subframe with the engine, transmission and front suspension can be dropped. In the rear, there are only four subframe attachment bolts. And any noise or vibration generated by SC's Traction-Lok differential is doubly isolated because it's rubber-mounted in the rubber-isolated rear subframe. Unfortunately, you also pick up one of the biggest disadvantages of a frame: significant extra weight. Adding further to the car's weight problem was the company's effort to provide vault like structural integrity with large roof-support rails and an ultra-rigid cowl. According to Ford's curb weight numbers, the new Thunderbird is almost embarrassingly heavy for a brand-new design. Does 700 lb heavier than a Mustang GT sound portly to you? Of course, this bulk only makes the prototype's acceleration times all the more amazing.

Under the all-new sheet metal is an all-new suspension system. Up front, the long, flat beak of the T-Bird rides on a short- and long-arm system rather than a more conventional MacPherson-strut arrangement as in last year's car. This system features variable-rate coil springs, a 1.2-in.-diameter anti-roll bar and electronically controlled nitrogen-pressurized gas shocks. Ford claims that the new system was adopted for several reasons. First, its lower profile allowed stylists to create a dramatically narrow nose. Second, it keeps the tire more vertical during aggressive cornering maneuvers ensuring a flatter tire contact patch for improved grip and longer tire life. Ford also claims that the new front suspension is considerably more dive-resistant. And finally, the new design provided slightly more (0.27 in.) wheel travel.

But the suspension arrangement in the rear is even less conventional for a rear-drive domestic sedan. It's a fully independent type with a large lower H-arm on which the variable-rate coil spring rides, and there is a smaller U channel upper arm. These arms are tied together by a cast aluminum knuckle. In addition, there's a 1.1-in.-diameter anti-roll bar and gas-pressurized shocks with electronically controlled damping. With 0.67 in. more travel and the rough-road absorption capability of this type suspension, bump steer in fast corners is reduced considerably.

On the rougher of the Dearborn test track's two-skid pads, we managed a quite good 0.85 lateral g number. That's the same handling territory occupied by Camaro IROC-ZS, Mazda RX-7 Turbos and the Toyota MR2's. Our waggle through the slalom course was also respectable at 61.0 mph. The car worked well through the slalom. In fact, although it felt rather bulky, it was easy to toss back and forth. And no matter what the speed, the new Bird seems to roll less than the old car. Much of the credit for the car's gripping power goes to the big P225/ 60VR- 16 Goodyear Eagles mounted on 7-in.-wide light alloy wheels.

After performing the handling hurdles, our tester remarked that the car's behavior was neutral to a fault. The T-Bird was competent-but not terribly entertaining. In fact, it reminded us a bit of the first time we drove the new Honda CRX.

Joe Cesarz, Ford's specialty-car suspension guru for midsize cars, detailed the philosophy behind the car's neutral handling. "When I tune a car's suspension, I don't want any funnies," he explained with a smile. "Sure we could have tuned a bit more oversteer character into the car's handling, and I could take about two seconds off my times on the handling course. But that'd be the type of suspension that would get most drivers in trouble. Instead, we installed our special toe link."

This extra bit of hardware between the lower H-arm and the subframe and a soft bushing in the H-arm's front pivot point help steer the rear wheels in the same direction as the front wheels during braking or acceleration. This helps eliminate the rear suspension's natural propensity to toe out-which would cause the back of the car to swing out.

"Actually, you'll find that type of oversteer behavior that enthusiast drivers like in early IRS vehicles," said Cesarz. "But, really, that kind of handling was essentially a flaw in older IRS-equipped sedans. And I think if you have a chance to drive the latest BMWs, you'll find that they're much more neutral in their handling behavior."

But what if a Thunderbird customer wanted a s a more of that oversteer handling "flaw"?

"Well, right now we've got a slight bit of initial toe-in at the rear to control that, " explained Cesarz. "But the owner could always try changing the curb toe settings to either 0 degrees or even toe-out. That's if he wanted the car to oversteer-and was willing to accept more tire wear."

When the T-Bird Turbo Coupe was last tested by R&T, we complained that the steering was "relatively uncommunicative." That's not true of the new speed sensitive power-assisted rack-and-pinion unit in the SC. Road feel could be a bit better, but the system is accurate and has quick on-center response. Indeed, the assist seemed just right for most driving situations This is achieved using an electronically controlled orifice in the steering pump, with a slow 17.4 1:1 ratio at the center of the rack and a faster 13.62:1 ratio out at the rack stops. At lower speeds, the microchip-tuned orifice is opened to provide extra boost for tight parking maneuvers. As vehicle speed increases, it closes down to allow the driver more road feel for better control. Another steering benefit-despite the longer wheelbase and wider track-is a 5.6-ft reduction in turning circle thanks to changes in the suspension geometry.

As for the SC's electronic suspension controls, we could definitely feel a ride difference between the soft and sport settings. The ride system is made by Tokico. A computer monitors vehicle speed, brake-line pressure, steering angle and engine-computer acceleration signals to determine the shock valving. There are just two-switch settings-, Auto and Firm. The automatic setting selects soft shock valving for a smooth ride and tauter valving when it reads the need. The firm position is simply an override that selects the firm setting in all driving modes.

Our cautious impression from this encounter with a pre production model is that the Thunderbird SC should provide powerful, smooth-riding, crisp-handling and stylish transport. Let's hear it for the risk-takers.

PRICE

List price, FOB Detroit...est $18,500
Price as tested................est $20,300
Price as tested includes std equip. (air cond, pwr adj seats, elect. adj shocks, elect. windowlifts, AM/FM stereo);elect. sunroof, central door locking, elect. adj mirrors, cassette player, tilt strg wheel, keyless door locks (est $1300)

ENGINE

Type....................supercharged ohv V-6
Bore x stroke, mm........96.8 x 86.0
Displacement, cc...........3797
Compression ratio, :1.....8.2
Bhp@ rmp, SAE net......210@4000
Torque, lb-ft@ rpm........315@2600
Fuel delivery...........electronic fuel-injection
Fuel requirement......unleaded, 92 pump oct
Exhaust-emission control equipment: 3-way catalytic converter, exhaust-gas recirculation, air injection

CHASSIS & BODY

Layout.........................front engine/rear drive
Body/frame...................unit steel
Brake system, f/r: 10.8-in. vented disks/10.0-in. vented disks, vacuum-assisted; ABS
Swept area, sq in. .........339
Wheels........................alloy, 16x7
Tires..Goodyear Eagle VR60, P225/60vr-16
Steering type......rack & pinion, pwr-assisted
Overall ratio, :1.............variable, 17.4-13.6
Turns, lock to lock..........2.8
Turning circle, ft.............35.6
Suspension, f/r: upper A-arms, lower lateral links, compliance struts, coil springs over tube shocks, anti-roll bar/upper lateral links, lower H-arms with toe links, coil springs, tube shocks, anti-roll bar

MANUFACTURER

Ford Motor Co, 300 Renaissance Center, Detroit, Mich. 48243

DRIVETRAIN

Transmission.................................5-speed manual
Gear ratios, :1, 5th (0.75)..................2.05
4th (1.00)......................................2.73
3rd (1.43)......................................3.90
2nd (2.32).....................................6.33
1st (3.75)......................................10.24
Final drive ratio, :1..........................2.73

INSTRUMENTATION

Instruments: 120-mph speedometer, 7000-rpm tach, boost press., oil level, coolant temp, fuel level

GENERAL

Curb weight, lb.............est 3770
Test weight..................est 3920
Weight distribution (w/driver), f/r,..est 53/47
Wheelbase, in...............est 113.0
Track, f/r......................61.4/60.2
Length.........................198.7
Width..........................72.7
Height..........................52.7
Ground clearance.............5.4
Trunk space, cu ft...........18.5
Fuel capacity, U.S. gal....19.0

ACCOMMODATION

Seating capacity, persons...........5
Head room, f/r, in....................36.5/34.5
Seat width, f/r.........................2 x 20.5/57.5
Seatback adjustment, deg..........70

CALCULATED DATA

Lb/bhp (test weight).......................est 18.7
Bhp/liter......................................55.3
Engine revs @ 60-mph in top gear....1600
R&T steering index........................01.00
Brake sweep area, sq in./ton...............173

ACCELERATION

Time to distance, sec
0-100 ft..................................3.2
0-500 ft..................................8.6
0-1320 ft (1/4 mi)....................15.9
Speed at end of 1/4 mi, mph.......88.5
Time to speed, sec
0-30 mph...............................2.5
0-40 mph...............................3.8
0-50 mph...............................5.5
0-60 mph...............................7.4
0-70 mph..............................10.4
0-80 mph..............................13.1
0-90 mph..............................16.4
0-100 mph............................20.8

SPEEDS IN GEARS

Maximum engine rpm...........5600
Rpm limiter............6250
5th gear (rpm) mph, est..(3525) 140
4th.............................(4700) 140
3rd............................117
2nd............................72
1st.............................45

FUEL ECONOMY

Normal driving, mpg................................est 17.0

BRAKES

Minimum stopping distances, ft
From 60 mph...............................................140
From 80 mph...............................................247
Control in panic stop...............................excellent
Pedal effort for 0.5g stop, lb...............................21
Fade: percent increase in pedal effort to maintain 0.5g
deceleration in 6 stops from 60 mph...................30
Overall brake rating..................................excellent

HANDLING

Lateral accel, 100-ft radius, g..........................0.85
Speed thru 700-ft slalom, mph.......................61.0

INTERIOR NOISE

Idle in neutral, dBA.........................................52
Maximum, 1st gear..........................................86
Constant 30 mph.............................................61
50 mph.........................................................67
70 mph.........................................................71
90 mph.........................................................73